Lawn mower sharpener



April 1934- E. KISTNER I 1,955,636

LAWN MOWER SHARPENER Filed May 21. 1932 2 Sheets-Sheet l ME. 11 21577? er 2 Sheets-Sheet 2 M. E. KISTNER LAWN MOWER Si IARPENER Filed May 21. 1932 April 17, 1934.

Patented Apr. 17, 1934 UNITED STATES PATENT OFFICE Application May 21,

4 Claims.

This invention relates to improvements in ma chines for sharpening cutting elements and pertains particularly to a lawn mower blade sharpener.

The primary object of the present invention is to provide a mower sharpener having a motor driven abrading wheel, which may be vertically adjusted relative to the blade being sharpened or adjusted in a horizontal plane to any desired angle before carrying out a sharpening operation.

Another object of the invention is to provide a machine of relatively simple construction which will be comparatively inexpensive to manufacture and easy to assemble and operate.

The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming part of this specification, with the understanding, however, that the invention is not confined to any strict conformity with the showing of the drawings but may be changed or modified so long as such changes or modifications mark no material departure from the salient features of the invention as expressed in the appended claims.

In the drawings:

Figure 1 is a view in front elevation of the machine embodying the present invention, parts thereof being in section or broken away;

Figure 2 is a view in top plan of the machine;

Figure 3 is a view in side elevation of the motor and emery wheel assembly and supporting means;

Figure 4 is a vertical sectional view through the headof one of the cutter reel supporting posts, showing the manner in which the cutter reel shaft is connected therewith;

Figure 5 is a sectional view taken on the line 55 of Figure 1;

Figure 6 is a sectional view taken on the line 6-6 of Figure 1;

Figure 7 is a view illustrating the method of mounting a mower cutter bar upon the shiftable plate or bar of the machine; 7

Figure 8 is a detail sectional View similar to Figure 4 but showing the method of mounting a reel shaft which is without centering depressions in its ends;

Figure 9 is a sectional detail of the bearing structure for the abrading wheel shaft.

Referring now more particularly to the drawings wherein like numerals of reference indicate corresponding parts throughout the several views, the numeral 1 indicates generally the base portion of the machine which is in the form of a table having the four legs, each of which is indicated 1932, Serial No. 612,795

by the numeral 2, which are preferably of angle iron material and which are connected by the top rectangular frame 3 which is also formed of angle iron material, and the intermediate reinforcing frame 4.

The angle iron material forming the top frame 3 has one side horizontally disposed and the other side extending downwardly to form a side flangeand in one corner of this frame there is vertically disposed a tubular casing 5 which is secured in place and in the angle of the adjacent leg 2, by the angle bolts 6, one of which is arranged in the plane of the depending flanges of the top frame 3 and the other in the plane of the depending flanges of the intermediate frame 4.

The bolts have each end threaded and extended through an adjacent frame flange as illustrated in Figure 5, to receive nuts '7 which are threaded thereon against the outer side of the flange so as to draw the bolt tight across the angle of the adjacent leg and across the vertical tubular casing 5. This tubular casing forms one unit of a vertically adjustable standard which is indicated generally by the numeral 8 and which will hereinafter be described in full detail. so,

Disposed transversely of the top frame 3 of the base structure is a unit 9 which constitutes a supporting guide for a shiftable implement supporting plate which is indicated as a whole by the numeral 10. This guide comprises two track members each of which is indicated by the numeral 11, which are arranged in spaced parallel relation, and which have their confronting faces provided with V grooves 12 which extend throughout the lengths thereof. At spaced intervals along the outer edges of these guide tracks are formed ears 13, certain of which position over the side bars or rails of the frame 3 to which they are secured by suitable nut and bolt fastening means 14. The other ears are arranged be- 'yond the sides of the frame 3 to which the cars 13 are attached through which the bolts 14 pass, and these ears are secured by the nut and bolt fastening elements 15 to the ends of brace bars 16 which have their other ends suitably secured 194 as indicated at 17 to the adjacent side bar of the intermediate bracing frame 4.

The slide plate 10 is relatively long as illustrated and its side edges are beveled at the top and bottom to form the V tongues 18. These V tongues slidably engage in the V grooves 12 of the tracks 9.

The plate or bar 10 is provided with the longitudinally extending, aligned and closed slots 19 and adjustably mounted upon this plate 10 is a pair of posts 20 each having a base 21 through which extends a bolt 22 which passes downwardly through the underlying slot and receives upon the under side of the plate a securing nut 23. The upper end-of each post 20 has a head 24 through which extends in a horizontal plane a passage 25 which is enlarged or reamed out as at 26 upon the end which is directed toward the adjacent post.

Removably positioned in the passage 25 of each post is a pin 27 which carries a pointed centering head 28, the points of the heads 28 being in opposed relation. These points are employed for supporting the mower blade reel horizontally between the posts 20 as will be hereinafter described.

Within the tubular casing 5 at a point somewhere adjacent the transverse center thereof, there is secured a threaded nut 29. Threadably engaged in this nut is a threaded shaft 30 which extends upwardly beyond the top of the casing 5 and surrounding this shaft 30 is a tube 31 which has its lower end slidably extended into the easing 5 as illustrated. The shaft 30 projects beyond the upper end of the tube 31 and has secured to it a collar 32 which rests upon the upper end of the tube, as illustrated.

At the upper end of the tube 31 is an arm 33 which is arranged at right angles to the tube and which at one end is integral with a sleeve '34. This sleeve fits over or receives the upper end of the tube 31 and has its top end closed except for a central opening 35 which is of sufficient size to pass the upper end of the shaft 30.

It will thus be seen that the collar 32 which is secured to the upper end of the shaft will be held between the upper end of the sleeve 34 and the upper end of the tube 31 but will be permitted to rotate. The sleeve 34 is secured against rotation on the tube by a set screw 36.

To the upper end of the shaft 30 above the sleeve 34 there is secured a crank 37 by means of which rotation of the shaft is effected so as to raise or lower the tube 31 and the arm carried thereby without turning the same.

The outer end of the arm 33 has formed integral therewith a plate 38 through which is a bolt passage 39 in which is located the bolt 40. "Suspended from the arm 33 is a bracket 41 which is substantially U-shaped and which has the side arms 42 and 43 substantially horizontally disposed. The side arm 42 of the bracket has an offset plate portion 44 which positions against the under face of the plate 38 and which is held in such position by the bolt 40. The lower arm '43 of the bracket is designed to support an electric motor 45 the shaft of which carries a pulley wheel 46 which is disposed beyond the adjacent side of the bracket.

Secured to and transversely of the under side of the lower arm 43 of the motor bracket is a bearing sleeve 47 in the ends of which suitable bearing units are housed. Through this sleeve and the bearing units therein there extends a shaft 48 upon one end of which is a pulley 49 which is connected by a suitable belt 50 with the pulley 46, while upon the other end is mounted an emery wheel 51. This emery wheel 51 is located with its center directly beneath the bolt 40 which forms the pivot about which the motor bracket 41 may be swung.

guide arm 54 which has one end extended across the periphery of the emery wheel 51 adjacent the lowest point thereof as indicated at 55.

In the use of the present mower sharpener, where the cutter blade carrying reel has a shaft having centering holes in the ends thereof this shaft is disposed between the pointed heads 28 carried by supporting posts 20, with the points of these heads engaging the center holes. The motor bracket 41 is then lowered to bring the periphery of the emery wheel into the proper position with respect to the reel blades by turning the crank 3'7 in the proper direction and this motor supporting bracket is also adjusted by oscillating it upon the supporting bolt 40 to locate the emery wheel 51 in the proper position transversely of the blade. After the motor 45 has been started the plate or bar 10 upon which the reel is carried is shifted longitudinally between the supporting rails 11 so as to move a selected blade across the periphery of the emery wheel to effect the desired grinding thereof, the reel being properly oscillated between the heads 28 to maintain the same in contact with the wheel.

In mowers having reel shafts not provided with centering recesses or depressions in the ends thereof, the support of the reel between the posts 20 is effected by removing the heads 28 and engaging the ends cf the shaft in the reamed out or counter-sunk ends 26 of the passages in the heads 24.

When it is desired to sharpen the cutter bar of the mower the heads 28 are removed from the posts 20 and the cutter bar is held in place between the heads 24 of the posts in the manner shown in Figure 'l by locating the end plates 56 against the heads 24 with the usual apertures 57 of these end plates aligned with the passages 25 of the post heads. The cutter bar and the part thereof which connects the end plates 56 and with which they are integral is indicated by the numeral 58. With the end plates 56 of the cutter bar in the position described there is then extended through the opening 57 and through the heads 44 the shank portions of screw hooks 59, the hook end thereof engaging the inner face of the cutter bar end plate in the manner illustrated, while the other end which is threaded receives a nut 60 which is drawn up against the supporting post head 24 in the manner shown. The edge 61 of the cutter bar may then be sharpened by moving the cutter bar and the supporting plate 10 longitudinally of the tracks 11 and beneath the emery wheel in the same manner as described in connection with the mower reel blades. 7

Not all types of lawn mowers have cutter bars with end plates like the plate 56, but some merely have holes-or apertures through which holding bolts are passed and in this form of bar the hook bolt or angle bolt 59 is passed through the bolt hole of the-cutter bar to maintain it in position;

While in the foregoing I have confined the de-' 'scription of the operation of the present device to the sharpening of lawn mower blades and cutter bars, it is, of course, to be understood that the same is not to be limited to such use for 'it will be readily apparent to those familiar with the art to which the invention relates that other cutting tools may be mounted upon the sliding plate or bar 10 and shifted in the proper manner beneath the emery wheel for sharpening.

As shown in Figure 9 the shaft 48 which passes through the bearing sleeve 47, is mounted adjacent its ends in a pair of bearings 48' and these 15::

are held in place by caps 48" which are secured in any suitable manner in the end of the sleeve and which retain against the adjacent bearings, the felt members 49'. The interior of the sleeve 4'7 is designed'to be filled with a suitable lubricant and by this means the bearings for the shaft 48 will be constantly lubricated and the operation of the machine thus materially improved.

Having thus described the invention, what is claimed is:

1. A machine for sharpening a cutting implement, comprising a base structure, a reciprocable body mounted upon said base, means carried by the body for securing an implement in position thereon, a tubular casing secured in vertical position to said base, a tube telescoping into the upper end of said casing, a screw shaft passing through said tube and into the casing, a threaded nut within the casing engaged by said shaft, an arm having a sleeve at one end engaged over the upper end of said tube, means for securing the sleeve to the tube, means preventing longitudinal movement of said screw shaft independently of said tube and sleeve, crank means for rotating said screw shaft, a bracket pivotally attached to the upper end of said arm, an electric motor carried by the bracket, an abrading wheel rotatably mounted on the bracket and disposed beneath the pivotal center thereof, and means for driving said abrading wheel from said motor.

2. A machine of the character described, comprising a leg supported frame, a pair of bar members disposed in spaced relation across and secured to said frame and having their opposing edges grooved, a flat longitudinally slotted bar disposed between the first bars and having its edges slidably engaging in said grooves, a pair of posts mounted upon said flat bar, securing means carried by said posts and engaging in said slot, said posts being adapted to support therebetween a lawn mower unit for sharpening, a telescopic standard disposed vertically in one corner of said frame, screw means for varying the length of said standard, a bracket arm secured at one end to said standard to be raised and lowered thereby and adapted to oscillate about a vertical axis, a

bracket structure pivotally attached to the other end of said arm, and a motor driven abrading unit carried by said bracket at an elevation above the element to be sharpened, the abrading element of said unit having the vertical axis upon which the unit supporting bracket oscillates passing therethrough.

3. In a machine of the character described, a table, a pair of bar members disposed in spaced parallel relation across and secured to the top of said table, said bars having their opposed faces grooved throughout, a flat bar member disposed between the first bars and having its longitudinal edges formed to be slidably received in said grooves, said flat bar having aligned longitudinally extending slots therein, a pair of posts mounted upon said fiat bar, means carried by each post for engagement in a slot to adjustably secure the post thereto, bearings carried by said posts, a standard secured to the table at one side of said bars, an arm swingably carried by the standard, and a grinding unit including an abrading wheel and means for transmitting rotary motion thereto, carried by said arm to be moved into engagement with a piece of work mounted between said bearings.

4. In a machine of the character described, a table, means carried by the table for supporting and moving a body of work over the top thereof, a standard secured to the table at one side of said means, means for adjusting the length of the standard, an arm attached at one end to the upper end of the standard and extending laterally therefrom over the work supporting means, a second arm pivotally secured at one end to the free end of the first arm to swing in a plane parallel therewith, a bracket depending from the free end of the second arm, an electric motor supported upon said bracket, a shaft rotatably mounted on the bracket beneath said motor, an abrading wheel carried by the shaft, driving means between the shaft and the motor, and a guide arm carried by the bracket and having an end terminating adjacent the periphery of the abrading wheel.

MAURICE E. KISTNER. 

